[2] After the division of the taifa, Mundhir allied with King Sancho Ramírez of Aragon and Navarre against his brother.

El Cid marched in a single day the 75 kilometres (47 mi) from Zaragoza to Peralta de Alcofea in a show of force directed against Mundhir.

The next day he marched 25 kilometres (16 mi) to Monzón, where he negotiated the surrender of the city, which marked its acceptance of al-Muʾtamin as lord.

In response, the ruler of Lleida, Mundhir formed a coalition with all of the Catalan counties save Pallars.

El Cid sent envoys to Mundhir and the Catalan princes offering money in exchange for lifting the siege and retiring to their own territory.

[11] The primary motivation for bribing the besiegers was that the allied army was much larger than the forces of Zaragoza and El Cid's personal mesnada [es] (retinue).

El Cid probably expected that the Catalans, who did not stand to gain territory anyway, could be persuaded to abandon their ally for money.

[14][15] In the Carmen, Almenar is the third fight of El Cid's career, after his combat with the anonymous Navarrese champion and his conflict with García Ordóñez.

Although later Castilian historiography claims that al-Muʾtamin acted on the urging of El Cid, the Historia Roderici mention no such thing.

[17] The Carmen Campi Doctoris was probably written shortly after the battle by a monk of Santa Maria de Ripoll, which lay within the territory of Ramon Berenguer II.